Anthropomorphic Phantoms
Modern radiation therapy techniques require precise and standard measurements to provide optimal care for cancer patients. Our anthropomorphic phantom tests, designed for different anatomical disease sites, involve the use of human-like phantoms, specially designed and constructed to simulate the response of human tissues to ionizing radiation. These tests provide an essential and independent evaluation of radiation therapy treatment quality and linear accelerator performance.
Each phantom design consists of a plastic shell or composite material in the appropriate anatomical shape and houses an imaging and dosimetry insert. The imaging inserts include target geometry and nearby critical structures that can be observed with CT. The phantom can be imaged with the imaging insert, and the images can be transferred to a treatment planning system for target volume delineation. The dosimetry insert used during treatment contains both radiochromic film and thermoluminescent dosimeters (TLDs) to measure both absolute dose and dose distributions to verify treatment accuracy.
The RQA Lab uses treatment planning information provided by the institution and the data gathered from TLD and film to analyze the institution’s ability to deliver its planned treatment.
To order an anthropomorphic phantom, please fill out a phantom request form.
Types of Phantoms
IMRT Head and Neck Phantom
Photon
The IMRT phantom is an all-purpose, broadly applicable, independent end-to-end verification of IMRT treatment delivery. While it is based on head and neck anatomy, it has been widely used as an all-purpose evaluation for IMRT. It has a primary target that is located adjacent to an organ at risk. There is also a secondary target that represents nearby lymph nodes and is treated to a lower dose. Each structure has film and TLD. The phantom should be imaged, planned, set up and treated as if it were a real patient. The acceptance criteria for the phantom audit are ±7% for the dose and ±7% /4 mm for the gamma index analysis. This phantom can help identify TPS problems as well as test the end-to-end calculation of IMRT delivery.
Proton
The proton H&N phantom is an all-purpose, broadly applicable, independent end-to-end verification of conformal proton treatment delivery. While it is based on head and neck anatomy, it has been widely used as an all-purpose evaluation for proton therapy. It has a horseshoe-shaped target that is located adjacent to several organs at risk: a spinal cord and parotid glands. Each structure has film and TLD. The phantom should be imaged, planned, set up and treated as if it were a real patient. The acceptance criteria for the phantom audit are ±7% for the dose and ±7% /4 mm for the gamma index analysis. This phantom can help identify TPS problems as well as test the end-to-end proton therapy delivery.
Moving Lung Phantom
Photon
The Thorax-Lung phantom is used as an independent peer-reviewed end-to-end test of 3DCRT or IMRT lung treatments. The phantom tests heterogeneity corrections and is designed for use with a motion platform to test motion management. It has an island tumor target located in the lung as well as a heart and spinal cord. Each structure has TLD and the target also contains film. The acceptance criteria for the phantom audit are ±7% for the dose and ±7% /5 mm for the gamma index analysis. This phantom can help identify systematic discrepancies in the TPS dose calculation.
Proton
The moving proton lung phantom is used as an independent peer-reviewed end-to-end test of proton therapy lung treatments. The phantom tests heterogeneity corrections and is designed for use with a motion platform to test motion management. It is available with either free breathing or breath hold respiratory patterns. It has an island tumor target located in the lung, with high density rib structures in the beam path. The target has TLD and film. The acceptance criteria for the phantom audit are ±7% for the dose and ±7% /5 mm for the gamma index analysis. This phantom can help identify systematic discrepancies in the TPS dose calculation and motion management.
Multitarget Moving Liver Phantom
Photon
This is one of our SBRT phantoms and is our most challenging. It has two small moving targets. The liver phantom is an independent end-to-end test of 3DCRT and IMRT treatment delivery. The phantom is designed for use with a motion platform to test motion management. It has a primary PTV, a secondary PTV and OARs. The phantom is imaged, planned, set up and treated as if it were a real patient.
The phantom analysis can help identify errors in the motion management process as well as setup errors, particularly those introduced during multifocal treatment.
Proton
The multi-target proton liver phantom is used as an independent peer-reviewed end-to-end test of proton liver treatments. The phantom is designed for use with a motion platform to test motion management. It is available with either free breathing or breath hold respiratory patterns. It has two tumor targets located in the liver as well as normal tissue avoidance structures. Each structure has TLD and the target also contains film. The acceptance criteria for the phantom audit are ±7% for the dose and ±7% /4 mm for the gamma index analysis. This phantom can help identify errors in clinical setup and motion management.
Prostate Phantom
Photon
The IMRT prostate phantom is an independent end-to-end test of IMRT treatment delivery. It has a prostate target that is located adjacent to several organs at risk: a bladder and rectum, as well as femoral heads. The phantom is imaged, planned, set up and treated as if it were a real patient. Rectal and bladder OARs simulate treatment planning challenges of prostate treatment.
Proton
The proton prostate phantom is an independent end-to-end verification of conformal proton treatment delivery. It has a prostate target that is located adjacent to several organs at risk: a bladder and rectum, as well as femoral heads. The target and femoral heads have TLD and the target also contains film. The phantom should be imaged, planned, set up and treated as if it were a real patient. The acceptance criteria for the phantom audit are ±7% for the dose and ±7% /4 mm for the gamma index analysis. This phantom can help identify TPS problems as well as test the end-to-end proton therapy delivery.
SBRT Spine Phantom
Photon
The spine phantom is used as an independent peer-reviewed end-to-end test of SBRT/SABR spine treatments. The spine insert includes a target adjacent to a structure representing a vertebral body. The spinal cord and esophagus are to be avoided. Each structure has TLD and the target also contains film. The acceptance criteria for the phantom audit are ±7% for the dose and ±5% /3 mm for the gamma index analysis. This phantom can help identify systematic discrepancies in the TPS dose calculation.
Proton
The pediatric proton spine phantom is used as an independent peer-reviewed end-to-end test of spinal treatments. The phantom includes a series of vertebral bodies and a spinal cord. The spinal cord is to be avoided. The phantom has TLD and film to measure delivered dose. The acceptance criteria for the phantom audit are ±5% for the dose, a ±5 mm distance-to-agreement for the range agreement, and ±5% /5 mm for the gamma index analysis. This phantom can help identify systematic discrepancies in the TPS dose calculation and beam range.
Stereotactic Radiosurgery Head Phantom
Photon
The SRS head phantom is used as an independent peer-reviewed end-to-end test of intracranial SRS treatments. The phantom can be used with GammaKnife, Cyberknife, Tomotherapy, or traditional delivery units. It has a spherical target 1.9 cm in diameter that holds film and TLD and evaluates both the dosimetric accuracy of the treatment as well as the positioning accuracy of the setup. The phantom has fiducials for alignment, and is designed to be imaged, planned, setup and treated as if it were a real patient. The acceptance criteria for the phantom audit are ±5% for the dose and ±5%/3 mm for the gamma index analysis.
Proton
The proton brain phantom is used as an independent peer-reviewed end-to-end test of intracranial treatments. The phantom can be used with traditional proton therapy delivery units. It has a spherical target 1.9 cm in diameter that holds film and TLD and evaluates both the dosimetric accuracy of the treatment as well as the positioning accuracy of the setup. The phantom has bony anatomy for alignment, and is designed to be imaged, planned, set up and treated as if it were a real patient. The acceptance criteria for the phantom audit are ±5% for the dose and ±5% /3 mm for the gamma index analysis.
Small Field Single Beam Phantom
The Small Field Single Beam is an independent peer-reviewed verification of output and depth dose test of small field sizes that are used in SRS or SBRT treatments. This test can evaluate the dose delivered (TPS versus measured) for SRS cones or MLC sizes from 12.5 mm to 60 mm. The phantom contains TLD at depths of 1.5 and 7.5 cm to evaluate PDD for the small field as well. The acceptance criteria for the audit is ±5%.
As compared to the SRS phantom, this test is more limited as it is based on a single beam irradiation of the detectors with the gantry at vertical rather than a clinical treatment delivery. However, this test allows for smaller fields to be evaluated and focuses just on output and TPS calculation and provides excellent focused evaluation of these aspects.
HDR Phantom
This phantom is for evaluating HDR practice. It tests accuracy of HDR dose delivery.
The HDR phantom is an independent peer-reviewed test of the HDR dose calculated by the HDR treatment planning system. The phantom has a catheter insert and holds OSLD at a distance of 2 cm from the catheter. The phantom is planned, set up and treated as if it were a real patient.
IGRT Isocenter Phantom
The IGRT phantom is used test how well the imaging system positions a target, as well as the coincidence of the imaging isocenter with the treatment isocenter. The test workflow mimics that of a clinical workflow and therefore provides a highly relevant test of the setup and alignment process.
The cube contains a tungsten ball in the center. Film on the outside of the phantom is used to perform a Winston-Lutz type test. The acceptance criteria for the audit is 1 mm for machines used for SRS/SBRT and 2 mm for IMRT machines, in accordance with TG-142. IGRT isocenter coincidence was identified as one of the top 10 most common deficiencies by IROC on-site audits, highlighting the need for careful evaluation of this aspect.
Photon
Instructions for the IGRT cube
Proton
CT-RLSP Phantom
Proton
The purpose of this phantom is to test the CT Number to Relative Linear Stopping Power (RLSP) or Stopping Power Ratio (SPR) conversion curve that your institution uses in the treatment planning system. The phantom is a cuboid containing seven materials spanning low to high CT numbers. The phantom is scanned on the institution’s CT scanner. The institution’s measured HU values and calibration curve are compared the RLSP for each phantom material that has been experimentally determined. The criterion for the phantom audit is ±15%.